Question: Solve for $x$ : $5\sqrt{x} + 6 = 9\sqrt{x} + 9$
Answer: Subtract $5\sqrt{x}$ from both sides: $(5\sqrt{x} + 6) - 5\sqrt{x} = (9\sqrt{x} + 9) - 5\sqrt{x}$ $6 = 4\sqrt{x} + 9$ Subtract $9$ from both sides: $6 - 9 = (4\sqrt{x} + 9) - 9$ $-3 = 4\sqrt{x}$ Divide both sides by $4$ $\frac{-3}{4} = \frac{4\sqrt{x}}{4}$ Simplify. $-\dfrac{3}{4} = \sqrt{x}$ The principal root of a number cannot be negative. So, there is no solution.